Nitrostarch demolition explosive



Patented Nov. 2, 1943 2,333,275 NITROSTARCH DEMOLITION EXPLOSIVE Walter 0. Snelling, Allentown, Pa., assignor to Trojan Powder Company, Allentown, Pa.

N Drawing. Application April 20, 1939, Serial No. 268,984

2 Claims.

This invention relates to explosives and has for its principal object the provision of a more efiicient demolition explosive.

A further object is to provide a very powerful, highly shattering, military demolition explosive suitable for breaking completely through a standard railroad rail when laid against such rail without mud or dirt stemming or the use of other confining means.

A still further object of the invention is to provide a demolition explosive employing at least twenty per cent of nitrated starch and stabilized with dicyandiamid.

The principal explosive ingredient of my invention in its preferred form is either nitrostarch or a mixture of nitrostarch and trinitrotoluene which together should make up approximately one-half of the total weight of the explosive. It is my preference that there shall be a minimum of of the nitrostarch in the formula for if a less quantity than this is used the characteristics change to such an extent that the demolition explosive is not entirely satisfactory. On the other hand, it is not necessary to use any T. N. T. at all but I do prefer to use substantially equal parts of nitrostarch and trinitrotoluene as this percentage gives a, v material which not only consolidates better in" the press but also enables me to make a better block and one that is somewhat harder than if nitrostarch alone were used.

The oxygen containing salt is preferably barium nitrate which should be coated with paraflin before mixing with the other elements of the explosive. While I prefer to use the barium nitrate alone as the oxygen carrying salt, and to have it form from 38% to 41% of the mixture forming the explosive, it is-possible to substitute a non-hygroscopic, gas-forming ingredient such for example as nitroguanidine or guanidine nitrate for a portion of the barium nitrate.

The addition of fine flakes of comminuted I metallic aluminum ranging from 2% to 4% of the Weight of the entire explosive is advantageous as this increases the energy'of the'explosive by the oxidation of this ingredient during the reaction of the other constituents:

The stabilizing element is preferably dicyandiamid ranging from one-half of one per cent to three times that value.

Coal dust of soft coal with not too great an ash content, running from 3% to 4% is advantageous as a combustible agent. I prefer to add from 1 to 3% of graphite and the total mately the same, i, e., sufficient to coat the nitrate but not running above 3%. The presence in the explosive of graphite permits the production of the. pellets under higher compression than would be possible without press explosions in absence of this constituent. In addition to its main function as a solid lubricant, the graphite also serves as a combustible agent being oxidized to one or both of the oxides of carbon.- It is more convenient to use the parafiin as a coating agent but obviously the demolition explosive will function satisfactorily with the chosen percentage of this ingredient present in other manner.

After the barium nitrate has been coated with I parafiin all the ingredients are thereupon mixed together for a suflicient time to thoroughly incorporate the various materials which make up the formula. The mixed material is then compressed into blocks to a density of at, least 1.70 and preferably appreciably greater than that amount. The size of the block is rather immaterial but I have found that blocks of 1, 2, or 4 ounces which can be combined into a. halfquantity of paramn used should be approxipound unit are most satisfactory. The blocks each have a hole completely through them .of a diameter slightly greater than a quarter of an inch in order to receive the usual detonator.

My preferred formula, not including moisture which preferably should be kept as low as possible, is nitrostarch 25%, trinitrotoluene 25%, barium nitrate 40%, aluminum flake 3%, coal dust 3%, dicyandiamid 1% and the balance of graphite and paraflin, not less than 1% of each. As previously stated it is convenient to replace not more than of the nitrostarch with an equivalent amount of trinitrotoluene in order to provide the denser blocks, that is the nitrostarch shall not be less than 25% of the total weight and the T. N. T. should not exceed 30% or 35% of the total weight.

What I claim is:

1. An explosive comprising roughly fifty parts of nitrostarch, forty parts barium nitrate, three parts coal dust, three parts of aluminum powder, one part substantially dry dicyandiamid and the balance graphite and paraffin, not less' than 1 part of each.

2. An explosive consisting of nitrostarch from 20% to 55%, trinitrotoluene from 0% to 35%, barium nitrate 35% to 45%, aluminum 1% to 5%, graphite to 4%,'Paraflin 56% to 4%, coal dust 1% to 6%, substantially dry dicyandlamid to 3%.

' WALTER O. SNELLING; 

